I'll add to it. The classic answer to your objection is "but as a species we'd have sooner or latter 1 billion steps worth of intellectual capital". Today someone gets to an intermediate result worth 1 million steps, tomorrow another million and so on.
But there's no guarantee that such "low IQ" intermediate steps exist. We do well with many classes of problems because of divide-and-conquer. But not all problems can be solved through divide-and-conquer.
For a rough analogy, see how AI plays chess and intermediate board positions often don't make sense to us. Imagine now an enormous chess-like game played in an enormous chess board where a match lasts longer than a lifetime and none of the intermediate steps make sense to any human.